Experimental Performance Analysis of a Thermal Energy Storage Using Phase Change Materials for Flexible Sector Coupling in Nordic Climates
Abstract
This study presents the laboratory characterisation of thermal energy storage (TES) using a phase change material (PCM) designed to be integrated with a heat pump, enabling flexible sector coupling (FSC) between renewable electricity generation and building thermal demands. The research focuses on the experimental performance evaluation of a PCM-TES configuration, which achieves a 69 kWh/m^3 storage capacity, designed for residential space heating applications. The PCM used is RT57HC, with a melting temperature between 57-60 ℃ and a melting enthalpy of 246 kJ/kg. The laboratory analysis here uses an electric heater to emulate a heat pump thermal input while utilising a water tank for heat rejection, enabling systematic assessment of storage behaviour across varied charging and discharging scenarios. Comprehensive testing protocols evaluated critical performance metrics, including thermal power delivery ranging from 5-25 kW, and operational efficiency of 88 %, under diverse flow rate and inlet temperature conditions. Experimental findings provide essential data for subsequent integration with actual heat pump systems at the chosen pilot site: a Live-in-Lab facility, advancing grid flexibility service capabilities, renewable energy utilisation of building energy systems and hence FSC with TES, in Nordic residential heating applications.
Keywords
thermal energy storage (TES), phase change material (PCM), flexible sector coupling (FSC), Heat pump (HP), renewable integration, energy flexibility